The Saugatuck "Cloud IT Services: Designed to Fail?" report said most cloud providers are architecting their systems in ways that satisfy the "adequate" expectations of individual users, while trying to woo enterprise and SMB IT organisations into placing ever-more-critical capabilities and operations into cloud-based services.

"Until these approaches change", said Saugatuck, "we are likely to see more, and likely more significant, cloud service outages based on server failure, resulting in a slowing down of enterprise-level business application and management migration to the cloud."

The company said that Apple's Siri is a "terrific example" of how the simplicity of a natural user interface "can mask the tremendous complexities required to enable and accomplish that simplicity".

But the recent Siri outage highlights the increasing reliance on the cloud for simple tasks such as getting directions or finding a telephone number, said Saugatuck, and may be "a terrific example of increasing business user expectations of cloud use, and a complacency toward cloud resiliency".

Apple blamed unexplained network problems for the Siri outage, in the same way RIM initially explained its global BlackBerry outage last month. However, it eventually became clear the BlackBerry problem was down to a single point of failure in a single UK data centre that affected the whole global BlackBerry user base.

Similar concerns have been expressed about Apple's iCloud and Siri service strategy, with Apple risking a similar fate to RIM if they pump iCloud too much, while trying to cram everything into their main North Carolina data centre.

There have been calls for RIM to build extra data centre capacity to cope with outages and Apple will no doubt face similar calls if Siri and other cloud-based services are regularly affected by outages.

But Saugatuck said that while individuals may come to expect and accept occasional failures, it "cannot be acceptable for business applications and operations management".

Its report recommended cloud suppliers build greater redundancy into their systems, and called for more extensive back-up and fail-over facilities to cope with outages.